Ji Chenchen, Wu Dandan, Liu Zhibo, Mi Hongyu, Liao Yinnian, Wu Mingzai, Cui Haonan, Li Xixian, Wu Tianlong, Bai Zhengyu
State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830017, People's Republic of China.
State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, People's Republic of China.
ACS Appl Mater Interfaces. 2022 May 12. doi: 10.1021/acsami.2c03323.
Aqueous zinc-ion hybrid supercapacitors (ZHSCs) represent one of the current research subjects because of their flame retardancy, ease of manufacturing, and exceptional roundtrip efficiency. With the evolution into real useful energy storage cells, the bottleneck factors of the corrosion and dendrite growth problems must be properly resolved for largely boosting their cycling life and energy efficiency. Herein, a natural polysaccharide strengthened hydrogel electrolyte (denoted as PAAm/agar/Zn(CFSO)) was engineered by designing an asymmetric dual network of covalently cross-linked polyacrylamide (denoted as PAAm) and physically cross-linked loose polysaccharide (e.g., agar) followed by intense uptake of Zn(CFSO) aqueous electrolyte. In this polymeric matrix, the PAAm chains are responsible for constructing the soft domains to immobilize the water molecules, and the agar component boosts the mechanical performance (by using its inherent reversible sacrificial bonds) and favors the electrolyte ion transport. Due to these reasons, the as-designed hydrogel electrolyte effectively inhibits the zinc dendrite growth, realizes the uniform Zn deposition, and affords a satisfactory ionic conductivity of 1.55 S m, excellent tensile strength (78.9 kPa at 507.7% stretchable), and high compression strength (118.0 kPa at 60.0% strain). Additionally, a biopolymer-derived N-doped carbon microsphere cathode material with a highly interconnected porous carbonaceous network (denoted as NC) was also synthesized, which delivers a high capacity of 92.8 mAh g, along with superb rate capability and long duration cycling lifespan (95.4% retention for 10000 cycles) in the aqueous Zn//NC ZHSC. More notably, with integrated merits of the PAAm/agar/Zn(CFSO) hydrogel electrolyte and NC, the as-built quasi-solid-state ZHSC achieves a high specific capacity of 73.4 mAh g and superior energy density of 61.3 Wh kg together with excellent cycling stability for 10000 cycles. This work demonstrated favorable practicability in the structural design of the hydrogel electrolytes and electrode materials for advanced ZHSC applications.
水系锌离子混合超级电容器（ZHSCs）因其阻燃性、易于制造和出色的往返效率而成为当前的研究课题之一。随着向实际可用储能电池的发展，腐蚀和枝晶生长问题等瓶颈因素必须得到妥善解决，以大幅提高其循环寿命和能量效率。在此，通过设计共价交联聚丙烯酰胺（表示为PAAm）和物理交联的疏松多糖（如琼脂）的不对称双网络，随后大量吸收Zn(CFSO)水系电解质，设计了一种天然多糖增强水凝胶电解质（表示为PAAm/琼脂/Zn(CFSO)）。在这种聚合物基质中，PAAm链负责构建软域以固定水分子，琼脂成分提高机械性能（通过利用其固有的可逆牺牲键）并有利于电解质离子传输。由于这些原因，所设计的水凝胶电解质有效地抑制了锌枝晶生长，实现了均匀的锌沉积，并提供了令人满意的1.55 S m离子电导率、出色的拉伸强度（在507.7%拉伸时为78.9 kPa）和高压缩强度（在60.0%应变时为118.0 kPa）。此外，还合成了一种具有高度互连多孔碳质网络的生物聚合物衍生的氮掺杂碳微球阴极材料（表示为NC），其在水系Zn//NC ZHSC中具有92.8 mAh g的高容量、出色的倍率性能和长循环寿命（10000次循环后保留95.4%）。更值得注意的是，凭借PAAm/琼脂/Zn(CFSO)水凝胶电解质和NC的综合优点，所构建的准固态ZHSC实现了73.4 mAh g的高比容量和61.3 Wh kg的优异能量密度，以及10000次循环的出色循环稳定性。这项工作在用于先进ZHSC应用的水凝胶电解质和电极材料的结构设计中展示了良好的实用性。
